How Organic Coating Systems Protect Against Corrosion

Author(s):  
Werner Funke
Keyword(s):  
2020 ◽  
Vol 117 (6) ◽  
pp. 610
Author(s):  
Nadia Hammouda ◽  
Kamel Belmokre

Organic coatings are widely employed in the corrosion protection of most metal surfaces, particularly steel. They provide a barrier against corrosive species present in the environment, due to their high resistance to oxygen, water and ions transport. This study focuses on the evaluation of corrosion protection performance of epoxy paint on the carbon steel surface in chloride environment (3% NaCl) by Electrochemical Impedance Spectroscopy (EIS). The electrochemical behavior of painted surface was estimated by EIS parameters that contained paint film resistance, paint film capacitance and double layer capacitance. On the basis of calculation using EIS spectrums it was observed that pore resistance (Rpore) decreased with the appearance of doubled layer capacitance (Cdl) due to the electrolyte penetration through the film. This was further confirmed by the decrease of diffusion resistance (Rd) which was also the indicator of the deterioration of paint film protectiveness. Microscopic analyses have shown that oxidation dominates the corroded surfaces.


Author(s):  
Kyoung-Ho Kim ◽  
Min-Soo Kang ◽  
Ji-Young Jang ◽  
Chang-Joon Lee ◽  
Yong-Won Lee ◽  
...  
Keyword(s):  

2010 ◽  
Vol 44-47 ◽  
pp. 610-613
Author(s):  
Qiang Liu ◽  
Bing Jian Zhang

The conservation of historic stone buildings and sculptures is receiving growing attention because of weathering. Now, the techniques for stone conservation are primarily achieved through the use of organic coating treatments. Although some defects of organic protective materials have been recognized, the further shortcoming is still short of awareness. Here we show our investigations of the side effect of organic coating treatments. Some kinds of common stones, including sandstone, tuff, granite, dolomite and marble, were selected as protected objects. Organic silicon compounds were used as protective coatings. The artificial weathering, including salting, freezing and heating, was designed. The treated stones’ decaying was investigated. The results reveal that the treated stone decaying is aggravated. Moreover, the destruction mechanism has been discussed.


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